Animal and Plant Toxins

A Small Dose of Animal and Plant Toxins

  • An Introduction to the Health Effects of Animal and Plant Toxins
    • Ancient Greek Athletes: "The Greek physician Galen is reputed to have prescribed 'the rear hooves of an Abyssinian ass, ground up, boiled in oil, and flavored with rose hips and rose petals' to improve performance."
    • Death of Socrates by Hemlock, 399 BCE: Charged with religious heresy and corrupting the morals of local youth. Active chemical is the alkaloid coniine which when ingested causes paralysis, convulsions, and potentially death.
    • Bee Stings: A honey bee has about 150µg of poison, but only a small fraction is typically injected. The faster the stinger is removed, the less the response.

Animal and Plant Toxins Dossier

Dossier - Animal Toxins

  • Name: Animal Venoms and Poisons
    • Use: medicinal uses
    • Source: spiders, insects, snakes, lizards, fish, and frogs
    • Recommended daily intake: none (not essential)
    • Absorption: varies but can be very fast, e.g. bites
    • Sensitive individuals: children (small size), previously sensitized
    • Toxicity/symptoms: varies
    • Regulatory facts: none
    • General facts: long history of use and desire to avoid, often accompanied by fear of the animal
    • Environmental: global distribution, concern about expanding distribution to new areas
    • Recommendations: follow precautions for avoiding contact

Dossier - Plant Toxins

  • Name: Plant Toxins
    • Use: medicinal uses
    • Source: wide variety of plants
    • Recommended daily intake: none (not essential)
    • Absorption: intestine, skin
    • Sensitive individuals: children (small size), previously sensitized
    • Toxicity/symptoms: varies
    • Regulatory facts: none
    • General facts: long history of use and desire to avoid
    • Environmental: global distribution, concern about expanding distribution to new areas
    • Recommendations: generally avoid; know the poisonous plants in area


Animal and Plant Toxins Chapter

PowerPoint Presentation

Arachnids (Scorpions, Spiders, Ticks)



Delivery & Venom




Stinger: neurotoxin, no enzymes

Localized pain, mostly dangerous to children


Latrodectus: Widow spiders (black, brown, red-legged spider)

Bite: neurotoxin, large molecular proteins

Localized pain, sweating, muscle cramps, decreased blood pressure


Loxosceles: Brown or violin spiders

Bite: complex mixture of enzymes

Serious tissue damage, attacks blood cells



Bite: saliva neurotoxin, transmits other diseases

Tick paralysis: causes weakness and difficulty walking (remove tick)



Poison or Venom


Moths and caterpillars

Irritating substance

Designed so they do not taste good


Variable: proteins, formic acid, others

Variable response: irritation, allergic response, tissue damage

Honey bees

Complex proteins

Swelling, allergic reaction


Formic acid





Venom & Delivery


Vipers (Viperidae)

Rattlesnakes, Water moccasins, Copperheads, Bushmasters

Very complex enzyme-based venoms, advanced delivery (hinged tubular fangs)

Swelling and necrosis at site, affects blood cells, hemorrhage, decreased blood pressure, shock


Cobras, Kraits, Coral Snakes

Neurotoxin (some very potent)
Fixed fangs, usually low dose

Nervous system effects, paralysis, numbness, respiratory failure

Marine Animals

Animal Class





Shellfish (filter-feeding mollusks)

Mussels, clams, oysters, scallops

Several kinds of toxin taken up from plankton (dinoflagellate)

See below



Paralytic Shellfish Poisoning (PSP)

Saxitoxin in their muscles

Numbness, respiratory paralysis

Sodium channel permeability


Diarrheic Shellfish Poisoning (DSP)

High-molecular-weight polyethers

Nausea, vomiting, diarrhea

Usually mild but annoying


Neurotoxic Shellfish Poisoning (NSP)


Numbness of mouth, muscular aches, dizziness



Amnesic Shellfish Poisoning (ASP)

Domoic acid

Confusion, memory loss, seizure, coma

Affects elderly


Jelly fish, anemona, coral


Sting, muscle cramps



Sea Snail (cigua) and some fish, oysters, and clams

Ciguatera, scaritoxin, and maitotoxin

Numbness, salivation, cardiovascular effects, respiratory paralysis

Inhibits acetyl cholinesterase


Puffer Fish (fugu, blowfish, toadfish), some frogs, starfish, octopus


Numbness, paralysis, respiratory failure, death

Decreased sodium channel permeability


Tuna, shark, swordfish

Mercury (toxicant)

Neurotoxic, reproductive effects

Not produced by fish itself, concentrated in muscle


a) Effects on Skin


Plant Examples

Toxin / Comment

Allergic dermatitis (plant itself): rashes, itchy skin

Philodendron, poison ivy, cashew, bulbs of daffodils, hyacinths, tulips

Antibody mediated after initial sensitization, very variable response. Allergens located on outer cells of plant.

Allergic rhinitis (pollen):  sniffles and sneezing, runny eyes

Ragweed (North America), mugwort (Europe), grasses

Antibody mediated, pollen widely distributed in air. Very common, can be debilitating.

Contact dermatitis

Oral: swelling and inflammation of mouth

Skin: pain and stinging sensation

Dumb cane (Dieffenbachia), Nettles (Urtica)

Calcium oxalate crystals coated with inflammatory proteins. Fine tubes contain histamine, acetylcholine, and serotonin

b) Effects on the Gastrointestinal System


Plant Examples

Toxin / Comment

Direct stomach irritation: nausea, vomiting, and diarrhea

California buckthorn (sacred bark), tung nut, horse chestnut, pokeweed

Emodin and esculine (toxins); oil from seeds, nuts; some medical uses, children are most often affected

Antimitotic (stops cell division): nausea, vomiting, confusion, delirium

Lily family, glory lily, crocus, may apple

Colchicine (gout treatment)

Lectin toxicity: nausea, diarrhea, headache, confusion, dehydration, death

Wisteria, castor bean (Ricinus communis)

Lectins bind to cell surfaces

Ricin: blocks protein synthesis, very toxic: 5 to 6 beans can kill a child

c) Effects on the Cardiovascular System


Plant Examples

Toxin / Comment

Digitalis-like glycosides: cardiac arrhythmias

Foxglove (Digitalis purpurea), squill, lily of the valley

Contain glycosides that are similar to digitalis:scillaren, convallatoxin

Heart nerves: decreased heart rate and blood pressure, general weakness

Lily, hellebore, death camas, heath family, monkshood, rhododendron

Alkaloids, aconitum, grayanotoxin (concentrated in honey)

Blood vessel constriction (vasoconstriction)

Mistletoe (berries contain toxin)

Holy or demonic effects on heart first described in 1597, toxin is called phoratoxin.

d) Effects on the Nervous System


Plant Examples

Toxin / Comment


Water hemlock, (parsley family), mint family

Cicutoxin affects potassium channels.

Monoterpenes in mint oils.

Stimulation from excitatory amino acids: headache, confusion, hallucinations

Red alga (red tide), green alga, mushrooms (Amanita family (fly agaric)), flat pea (Lathyrus)

Kainic acid, domoic acid: concentrated in shell fish

Ibotenic acid: muscarinic (hallucinations)

Lathyrism: motor neuron degeneration

Aberrant behavior, excitability, muscle weakness, death

Locoweed (found in Australia and Western U.S)

Swainsonine toxin: liver enzyme inhibitor, well known to affect cattle


Coffee bean, tea, cola nut

Caffeine: most widely consumed stimulant in the world

Death (neurotoxic)

Poison hemlock (Conium maculatum)

Coniine: neurotoxic alkaloid, used by Socrates

Paralysis (demyelination of peripheral nerves)

Buckthorn, coyotillo, tullidora (US, Mexico)

Anthracenones: attack the myelin that surrounds the peripheral nerves

Atropine-like effects: dry mouth, dilated pupils, confusion, hallucinations, memory lose

Solanaceae family: jimsonweed, henbane, deadly nightshade (Atropa belladonna), angel's trumpet (atropine and scopolamine)

Clinical effects of many of the plants recognized since ancient times.

Deaths are rare but children vulnerable.
Hallucinations from muscarine and psilocybin; angel's trumpet contains atropine and scopolamine.

Neuromuscular effects: mild stimulation to muscle paralysis, respiratory failure (curare), death

Tobacco, Strychnos family (curare), blue-green algae (anatoxin-A)

Nicotine blocks acetylcholine receptors; curare used as a hunting poison (very potent receptor blocker)

e) Effects on the Liver


Plant Examples

Toxin / Comment

Hepatitis and cirrhosis of liver from contaminated grain

Ragwort or groundsel

Pyrrolizidine alkaloids attack liver vessels: affects humans and cattle but some species resistant

Liver failure and death

Mushrooms: Death cap" (Amanita phalloides)

Amatoxin and phalloidin affect RNA and protein synthesis

Liver cancer

Fungus that grows on peanuts, walnuts, etc.

Aflatoxins: produced by fungus in poorly stored grain

f) Effects on the Reproductive System

Organ System


Plant Examples

Toxin / Comment

Reproductive Effects

Teratogen: malformations in offspring (sheep)

Veratrum californicum (native to North America)

Veratrum: blocks cholesterol synthesis, seen in offspring of mountain sheep


Abortifacients: cause fetal abortions

Legumes (Astrogalus), bitter melon seeds (Momordica)

Swainsonine toxin stops cell division; lectins halt protein synthesis (used by humans)

More Information and References

European, Asian, and international Agencies

North American Agencies

  • Health Canada. Drugs and Health Products. Natural Health Products Regulations work to "ensure that all Canadians have ready access to natural health products that are safe, effective, and of high quality, while respecting freedom of choice and philosophical and cultural diversity."
  • US Food and Drug Administration (FDA). Seafood. Site has information on seafood health and safety issues.
  • Northwest Fisheries Science Center (NWFSC). Harmful Algal Bloom Program. NWFSC Harmful Algal Bloom Program, part of the US National Oceanic and Atmospheric Administration, provides information related to algal blooms.

Non-government Organizations

  • Texas A&M University System. National Natural Toxins Research Center. The National Natural Toxins Research Center has a mission to provide global research, training & resources that will lead to the discovery of medically important toxins found in snake venoms.
  • Cornell University. Plants Poisonous to Livestock. This site "includes plant images, pictures of affected animals and presentations concerning the botany, chemistry, toxicology, diagnosis and prevention of poisoning of animals by plants and other natural flora (fungi, etc.)"
  • Alternative Medicine Foundation, Inc. HerbMed®. "HerbMed®—an interactive, electronic herbal database—provides hyperlinked access to the scientific data underlying the use of herbs for health. It is an evidence-based information resource for professionals, researchers, and general public."
  • The Vaults of Erowid. The Vaults of Erowid website contains information on a wide variety of natural plants and chemicals.


  • Handbook of Clinical Toxicology of Animal Venoms and Poisons by J. Meier (Editor), Julian White (Editor). New York: Informa HealthCare, 1995.
  • Mebs, Dietrich. Venomous and Poisonous Animals: A Handbook for Biologists, Toxicologists and Toxinologists, Physicians and Pharmacists. Medpharm, 2002.
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